1. Field of the Invention
The present invention relates to a rotating electrical component, such as a variable resistor, rotary encoder, etc., suitable for use in such an electric cooking appliance as an electric range.
2. Description of Related Art
In a conventional portable electronic equipment such as a radio receiver, a transceiver, etc., if the power switch is carelessly pressed to on and the user does not notice it, battery power will be wasted. To obviate the above-described disadvantage, a switch described below has been disclosed in Japanese Utility Model Publication No. Sho 63-18095.
In the switch disclosed in Japanese Utility Model Publication No. Sho 63-18095, as shown in FIGS. 12 and 13, a cylindrical support member 31 is comprised of a projecting piece 32 mounted on the outer peripheral portion for operating the switch, a projection-recess portion 33, a flange 34 formed on the inside surface, and a pair of recesses 35 mutually facing on both sides of the shaft hole and formed in the lower surface of the flange so as to be positioned on the circumference of the same diameter.
The sliding member 36 has a small-diameter shaft 37, a large-diameter shaft 38, a flange 39 located between the small-diameter shaft 37 and the large-diameter shaft 38, and a pair of projections 40 formed on the upper surface of the flange 39 in opposite positions on both sides of the small-diameter shaft 37.
The sliding member 36 is inserted in the support member 31. In this state the sliding member 36 thus installed is rotatable and axially movable. And the pair of projections 40 can be engaged with, and disengaged from, the pair of recesses 35.
Furthermore the sliding member 36 thus installed is pressed against the flange 34 of the support member 31 by the force of a spring 42 interposed between a bottom member 41 and the flange 39.
Above the sliding member 36 are mounted a knob 43 and a push member 44, and furthermore a ball 46 loaded with a spring 45 is placed oppositely to the projection-recess portion 33 of the support member 31, thereby constituting a click mechanism.
The switch operation stated above first presses the push member 44 against the force of the spring 42 to move the slide member 36 in the axial direction, disengaging the projection 40 from the recess 35, and thereafter the knob 43 is turned to turn the slide member 36 to thereby rotate the support member 31.
Then, the support member 31 is operated with a click by the click mechanism and the projecting piece 32 rotates to change over the contact of the switch not shown.
As the knob 43 is turned back to the original position, the slide member 36 also moves back to engage the projection 40 with the recess 35.
That is, the switch is first pushed and then turned so as not to be carelessly operated to on.
The above-described conventional switch has such a disadvantage that because the pair of recesses 35 and the projections 40 are formed on a circumference of the same diameter, the projection 40 is engaged with the recess 35 within the 180-degree range of rotation of the slide member 36; and accordingly the slide member 36 has a narrow operation range.
The bottom member 41 is needed beside the slide member 36 to install the spring 42, which increases components count and cost, resulting in low productivity.
Furthermore, there is such a drawback that the support member 31, being designed to be rotated, needs a member for supporting itself, thereby increasing the components count; and moreover on the outer periphery of the support member 31 the projecting piece 32 is formed for switch operation or the projection-recess portion 33 is provided as the click mechanism, making the structure large and complicated.